Are there any relationship between the grade of mucoid degeneration and biochemical marker levels in synovial fluid at meniscal tears?

INTRODUCTION:The purpose of this study; to examine the relationship between mucoid degeneration and biochemical environment in the synovial fluid with biochemical analysis at meniscal tears which have mucoid degeneration confirmed histopathologically. Our hypothesis is, in mucoid degenerated meniscal tears, synovial fluid biochemical marker concentrations are higher.PATIENTS and METHODS:Synovial fluids were aspirated from cases who have isolated meniscal tears before arthroscopy. If needed, arthroscopic partial menisectomy were done and the samples sent to pathology department. According to Copenhaver grading system, grade 1 and 2 cases produce group A (n=13) and grade 3 cases produce groupB (n=19). The control group (group C, n= 9) was made by the other nontraumatic and asymptomatic knees of the patients. The synovial fluid samples examined at the biochemistry laboratory. MMP-3 (matrix metalloproteinase-3), TIMP-1 (tissue inhibitor matrix metalloproteinase-1), COMP (cartilage oligomeric matrix protein) and proteoglycan fragment levels were examined. The results are statistically analysed with non-parametric Mann Whitney U test.RESULTS:Synovial fluid proteoglycan fragment levels are significantly higher in grade 3 mucoid degenerated meniscal tear group (group B) than grade 1 and 2 mucoid degenerated meniscal tear group (group A) (p=0.044). There were no significant difference between group A and B for MMP-3, TIMP-1 and COMP levels. Between group B and C (control group), there were no significant difference for biochemical marker levels but for the proteoglycan fragment levels, p value is at the level of significance (p=0.055). Between group A and C (control group), there were no significant difference for biochemical marker levels. At traumatic meniscal tear cases the MMP-3 levels are significantly higher than atraumatic meniscal tear cases (p=0.025). At group A and B, there were high positive correlation between MMP-3 and TIMP-1 levels.DISCUSSION:In our study, relationship found between high grade mucoid degeneration and synovial fluid fragment concentration. High levels of proteoglycan fragments are either the cause or the result of mucoid degeneration. Meniscal mucoid degeneration may associate with the generalized knee degeneration.Key words: biochemical markers, synovial fluid, meniscal mucoid degeneration, meniscal tear